1. Field of the Invention
The present invention relates generally to a gasdynamic laser system for a hypersonic vehicle which operates at wavelengths shorter than 10.6.mu. meters, down to wavelengths of less than 1.mu. meter.
More particularly, the subject invention pertains to a gasdynamic laser system for a hypersonic vehicle as described wherein high enthalpy ram air provides an energy source for thermodynamic excitation of the laser gases, and also, when required, drives an electrical generator for electronic excitation of the lasing species.
2. Discussion of the Prior Art
In the late nineteen seventies, the Grumman Corporate Research Center, in cooperation with the NASA Langley Research Center, conceptualized an Advanced Flow Laser (AFL) and a Mixing Advanced Flow Laser (MAFL) for fleet defense against air-launched missiles and other missions. In both concepts, a high energy CO.sub.2 laser is incorporated in a hypersonic (i.e., flight speeds greater than five times the local speed of sound), high altitude (i.e., greater than 35,000 ft. altitude) vehicle. During operation, energy from the high enthalpy ram air produces excited states in the N.sub.2 molecules which are transferred by resonance to unstable, excited states of CO.sub.2 constituents in the gas flowing through the lasing cavity. Carbon and water are required to be added to the lasing gas mixture, which flows through an appropriate expansion channel to produce and maintain the population inversion resulting in a 10.6 .mu.m output (CO.sub.2 laser). Because the laser beam intensity on target is inversely proportional to the square of the wavelength, the CO.sub.2 laser is unsuited for missions where extremely long laser beam range is required. Moreover, this technology and approach could not be utilized below the 10.6 .mu.m wavelength, which results in severe limitations on the extent of its practical usefulness.